The two projectors reviewed here use a new kind of projection technology called reflective LCD. A reflective LCD works similarly to the transmissive LCD, but offers one major advantage -- the aperture ratio isn't affected as resolution increases.
A transmissive LCD creates images by letting light pass through a "net" of tiny wires and transistors, forming images by opening or closing pixels electronically. As transmissive LCD manufacturers cram higher resolutions into 1.3-inch LCD panels, the network of wires and transistors becomes more dense -- resulting in a dramatic drop of aperture and less light on the screen. A typical XGA-resolution LCD, for example, struggles to let even 50 percent of the light through the LCD.
A reflective LCD, on the other hand, hides all the transistors and wire beneath a smooth reflective layer of silicon, forming images by turning on or turning off the reflecting pixel. Theoretically, this should result in aperture ratios of more than 90 percent because there's no net to block the light. In reality, today's first-generation reflective LCD products can't match the efficiency of the top transmissive LCDs using "micro-lenses" embedded in each pixel to minimize light loss.
Nonetheless, today's reflective LCD projectors are the only "imagers" that offer true SXGA 1,280 x 1,024 resolution in a 1.3-inch panel, and in the future this technology may give transmissive LCD a run for its money.
In Focus LP740
Pros:Bright, high-res projector with easy workstation connectivity. Includes 13W3 connectors for IBM, Sun and SGI workstations.
Cons: Larger, heavier, more expensive than others in its class. Color saturation needs improvement. Noticeable onscreen stripes and dots from LCDs' construction and drive method.
Weight: 31.4 pounds.
LCD size and Resolution: 1.3-inch, SXGA 1,280 x 1,024.
Optics: Three reflective panels, x-cube-based, dichroic system, separate polarizing beam splitters and optical integrator.Manual zoom lens.
Lamp: 250-watt, DC metal-halide lamp.
Average Measured Brightness: 471 ANSI lumens.
Measured ANSI 16-pt. contrast: 82-to-1.
Connections: Computer data and stereo audio, S-VHS and composite video with stereo audio inputs. Includes RS-232 connection port and "wired" remote-control connector.
Video compatibility: Accepts most video sources up to 1,280 x 1,024 lines (including most graphics workstation signals).
Speakers: Two 1-watt built-in speakers.
Included accessories: IR remote control.
In Focus' relationship with Japan's Advanced Peripherals Technologies Inc. (APTi) -- a joint venture between IBM and Toshiba -- has netted the company more than just a distributor for its products in Japan. APTi is now the manufacturer of the In Focus LP740, which uses reflective, silicon-based LCDs produced by IBM-Japan. APTi also sells a similar product in Japan called the AP-1200SX.
I measured the In Focus LP740's brightness at 529 ANSI lumens in its wide-zoom setting, which is about 10 percent less than the manufacturer's claimed brightness of 600 lumens. I also recorded an average between wide- and narrow-zoom settings of 471 ANSI lumens. With a 250-watt lamp, that's an average of less than two lumens per watt.
Set for optimal performance, this projector provided a reasonable contrast ratio of 82-to-1. However, with the projected images in sharp focus, vertical lines are visible between every two columns of pixels. This is a result of the driving method used in the IBM-developed LCDs, in which every two columns are kept at the same electrical polarity. If the lines become too noticeable, though, a "smooth mode" can be selected that alternates each column's polarity and makes the lines go away, along with the contrast. Still, I preferred the slight vertical lines to the washed-out images in smooth mode.
In addition to the vertical lines, a grid of dots can be seen on some images (this is especially noticeable on images with a lot of even gray half-tones). These dots are caused by the "spacer posts" used to keep the LCD fluid at a uniform thickness between the reflective silicon back plane and the top cover glass. According to IBM -- which created the posts as part of its CMOS manufacturing process -- programs are under way to revise the LCD's driving method and manufacturing processes to minimize or eliminate these lines and dots.
I measured the corner brightness of this unit at much lower (54 percent) than the 80 to 90 percent usually obtained from the best three-panel projectors. This was surprising because the LP740 uses a large, 3-inch, 5 x 4-segment integrator to minimize hot spots.
The color saturation measured in at 15.76 units, which was also lower than I expected. Some three-panel LCD products can get close to 17 or 18. The LP740's white point was acceptable at 5.32 units away from the standard D65 white. And, like many features on this projector, the white point was very adjustable through the onscreen menu system.
Besides the lines and spots problem mentioned above, the LP740's black colors seem to be off as well. The darker colors take on a purple hue, depending on which brightness setting is used.
In addition, the LP740's video-processing circuits had a gain problem. Even though the video images appeared to be smoothly expanded from NTSC's 320 x 240 pixels to the LP740's 1,280 x 1,024, they lost some brightness in the process. When asked about this, In Focus said the problem was caused by a bug in its gamma correction software, and was only present in the first few units shipped. In any event, it is easily corrected once detected.
Pros: Bright, full featured, all aspect ratio SXGA projector at a competitive price. Includes a component video interface for Pro AV, DVD and DTV applications. Great color saturation with excellent white point and good contrast.
Cons: Composite and S-VHS video processing looked noisy in prototype.
Weight: 28.6 pounds.
LCD size and resolution: 0.9-inch SXGA 1,360 x 1,024.
Optics: Three reflective panels, x-cube-based, dichroic system with separate polarizing beam splitters and optical integrator. Motorized zoom and focus lens.
Lamp: 400-watt, ceramic-type Xenon lamp.
Average measured brightness: 711 ANSI lumens.
Measured ANSI 16-point contrast: 90-to-1.
Connections: One 15-pin computer data and one 5 BNC computer data, both with stereo-audio inputs; three BNC Y, Pb, Pr component video, mini-din S-VHS and BNC composite video with stereo-audio inputs. Includes 15-pin monitor and stereo audio outputs as well as RS-232 control port and "wired" remote-control port.
Video compatibility: Accepts most popular video sources up to SXGA 1,360 x 1,024 signals.
Speakers: Two 1-watt built-in speakers.
Included accessories: IR remote and various adapters.
The Japan Victor Company (JVC) has used its experience producing liquid crystals for the Hughes-JVC line of large-venue light-valve projectors to produce a reflective LCD with outstanding image quality for its new Digital Image Light Amplifier (D-ILA), projector called the DLA-G10 (also being marketed by Hughes-JVC as the D-ILA G1000).
The DLA-G10 supposedly uses the same kind of high-contrast liquid-crystal material used in the big ILA projectors -- and it shows. JVC's reflective LCD is smaller (0.9 inches) than the 1.3-inch SXGA LCD developed by IBM, but actually has more resolution.
I measured a prototype DLA's brightness at 714 ANSI lumens in the brightest zoom setting, and an average between wide- and narrow-zoom settings of 711 ANSI lumens. JVC has been advertising this projector as a 1,000-lumen unit, but I didn't measure anywhere near that. I discussed this with JVC and the company attributed it to the prototype nature of the unit. Before shipping production units to North America, JVC intends to increase the brightness to a level closer to 1,000 lumens.
Set for optimal performance, I measured the contrast ratio at 90-to-1. Unlike the LP740's purplish-black colors, the DLA produced more neutral blacks, along with a complete absence of lines or spots. If JVC is using spacers in its LCD's manufacturing process, they can't be seen because they're on the edge. Truth is, most 1.3- and 0.9-inch LCDs used in three-panel projectors today do not use spacers in the image area; IBM's posts are the exception.
IBM is going to have to hurry if they want to catch up with JVC's image quality. Even the prototype unit from JVC looked better than the production unit I received from In Focus.
The corner brightness of this unit was much higher (91 percent) than that of the In Focus LP740, and higher than the 80 to 90 percent usually obtained from the best three-panel projectors.
The color saturation was also better than I expected. I measured 17.26 units of color saturation, which is right up there with the best three-panel LCD products. The DLA's white point was also very good at only 3.8 units away from the standard D65 white. Like the LP740, the DLA's white point can be adjusted, but only by selecting one of three standard settings, whereas the LP740's color settings are continuously variable.
There were only a few things I didn't like on this fine projector. I tried all the video interfaces, and although the component video inputs from a DVD looked OK, there was more aliasing than there should be. I observed a demonstration of the DLA connected to DTV signals that looked fairly clean, but NTSC signals with either the composite or S-VHS input looked too noisy. JVC needs to improve its video circuits to match the rest of its projector's overall image quality. JVC supplied another unit, however, that fixed all of these problems, giving excellent video with any input.
William Bohannon, chief scientist at Escondido, Calif.-based Manx Research (760.735.9678), has more than 25 years of experience in the computer and projector industry. As chief scientist for Display Products at Proxima Corp. from 1989 to 1994, he developed important business relationships with several Japanese laboratories and companies. His career also includes positions at TRW, Hughes Aircraft and Kappa Systems.